NORTHAMPTON — Vermont Sen. Bernie Sanders does not believe his support for the working class makes him unusual.

Though he finds that many people who call themselves progressives believe they are in the minority, he does not believe this about himself, he said.

“Every idea I ever espoused, I believe, is what the vast majority of our country believe,” Sanders told a crowd of around 400 people who filled the sanctuary at First Churches Friday for “A Conversation with Senator Bernie Sanders,” an event sponsored by The Nation magazine, Progressive Democrats of America, and radio station WHMP.

“The Koch brothers and their friends are a small minority. Never, ever forget that,” Sanders said.

The independent senator was invited to Northampton by Tim Carpenter, founder of the Progressive Democrats of America, to speak as part of the national organization’s 10th anniversary celebration. Carpenter, of Florence, died April 28 at the age of 55.

Friday’s event featured a dialogue between Sanders and John Nichols, Washington correspondent for The Nation, on what the senator believes to be the important issues facing this country. Audience members were also given the opportunity to ask questions.

Sanders, 72, drew national attention when he told Nichols in a March interview that he is “prepared to run for president of the United States,” including a petition organized by Carpenter urging Sanders to run.

During Friday’s conversation, Sanders spoke about growing up in a working-class family in Brooklyn, and expressed his support for expanding retirement benefits and making sure everyone has access to health care and education.

“In the U.S., we spend almost as much as the rest of the world combined on defense,” Sanders said.

He pointed to a growing income disparity between social classes in the United States, alluding to a statistic on his website showing that the top 1 percent of American income earners owns more than 35 percent of all of the nation’s wealth, while the bottom 60 percent owns only 2.3 percent.

He said he believes the most important current issue is overturning Citizens United, the Supreme Court ruling that removed limits on political spending by corporations.

While he does not believe Scandinavian countries such as Norway have created “utopia,” he said, he believes the United States can learn from these countries’ abilities to offer strong retirement programs and free college education.

He criticized the media for not showing this, and added that in his 23 years as a member of Congress — 16 in the House and seven in the Senate — no reporter has asked him what he is going to do to eliminate poverty and to make sure everyone has health care.

When Sanders noted the rising cost of college education and attributed it to increasing student debt, audience member Johanna Hibbs, who came from Stafford Springs, Connecticut, for the event, called out that she is now $100,000 in debt after obtaining bachelor’s and master’s degrees.

In an interview outside the sanctuary, Hibbs, 29, said she took the first full-time job she could after finishing school, but at $30,000 a year, still could not pay all of her bills. She has since had to move away from that job because she could not pay the rent, and now works part-time jobs, she said.

Michelle Serra of Florence, a member of Progressive Democrats of America and an event organizer, said she believes Sanders is able to present complex issues in a straightforward way.

“I just really feel that he is the real thing,” she said. “He’s talking about issues that affect all of us.”

On Saturday, the Progressive Democrats of America will also sponsor an all-day celebration of their 10th anniversary beginning at 9 a.m. at First Churches. Speakers will include Sanders, Jim Hightower, Rep. James McGovern, Thom Hartmann and others who will talk about topics such as health care, the media and Congress. There will be a memorial for Carpenter from 3:30 to 5:30 p.m.